Power-driven toothbrush



Nov. 26, 1929. E.- s. BROTHERS POWER DRIVEN TOOTHBRUSH Filed May 9, 1927 2 Sheets-Sheet Hill! lIlHll EYS.

Nov. 26, 1929.

E. s. BROTHERS POWER DRIVEN TOOTHBRUSH Filed May 9, 1927 2 Sheets-Sheet 2 mw i ATT NEYS.

Patented Nov. 26, 1929 l v I Uldtffifi STATES PATENT OFFIQE EDWIN S. BROTHERS, OF BROOKLYN, NEW YORK POWER-DRIVEN TOOTHBR'USH Application filed May 9, 1927. Serial No. 189,802.

This invention is a power driven tooth Fifth, to provide driving means for the brusn adapted for use 1n the home. Power brush which cannot posslbly cause injury to brushes for the cleaning of the teeth have the parts of the mouth, lips, gums, etc. heretofore been suggested. They generally Sixth, to provide an efficient guard to pro- 5 embody a suitable flexible shaft provided at tect all parts of the structure except the. brush 55 the end with a hand piece coaxial of which from contact with the parts of the mouth. the power shaft is mounted and the brush is The foregoing objects and others are accarried directly on the power shaft with the complished in a structure which will be hereaxis of the brush coaxial with the hand piece. inafter more fully set forth in the following. 1 In the brushing of teeth, it is important detailed description and in the appended to that the bristles of the brush travel in a diclaims. rection from the gums toward the free edges The accompanying drawing illustrates difof the teeth. In order to operate a power ferent practical embodiments of the invenbrush of the character described so as to brush tion, but the constructions therein shown are teeth in this manner, it has heretofore been to be understood as illustrative, only, and IlOt 65 necessary to provide a prime mover which was as defining the limits of the invention. reversible, that is to say, a prime mover which Figure 1 is a central section of a device emwould operate the shaft or brush first in one bodying the present invention. direction to brush certain teeth and then to Figure 2 is a perspective view showing the reverse the operation of the brush in the brush element of the structure. brushing of other teeth. Figure 8 is a like view illustrating the hub l/Vith the foregoing considerations in mind, portion of the brush. the objects of the present invention may be Figure 4 is a section on the line 44: of briefly enumerated as follows. Figure 3. 25 First, to provide apower tooth brush which Figure 5 is a central section through the may be operated in an eflicient manner withflexible shaft of this invention. out requiring reversal of rotation of the Figure 6 is a side elevation of the structure drive shaft of the brush in the efficient brushshown in Figures 1, 7 and 8. ing of all the teeth. This is accomplished by Figure 7 is a view similar to Figure 1, but 30 mounting the brush at substantially right illustrating a different form of brush and so angles to the handle. connection with the shaft.

Second, to provide highly eflicient and Figure 8 is a front elevation of the structure novel means for driving a right angularly disof Figure 7; and, posed brush from a flexible shaft extending Figure 9 is a section on the line 99 of through the handle and without necessitating Figure 7 the employment of universal joints, gears Referring to the drawings, 1 designates a or other expensive and disadvantageous mehandle frame which is shown in the form of a chanical connections. fork or yoke having two arms 2 and 3 and Third, to provide for the mounting of a a stem 4. The stem 4 is secured to the conbrush in a detachable manner upon a flexible duit 5 by a flexible shaft 6, which extends shaft in right angular relation to the handle from any suitable prime mover through con and to permit the brush to be readily mounted duit 5 to the handle frame 1. and demounted with respect to the handle in In practically carrying out this invention, order that different members of the family it is necessary that the flexible shaft turn a may readily and expeditiously substitute relatively sharp angle at the end of the hanw their own individual brushes. dle frame. My experience with flexible Fourth, to provide an efficient form of shafts has been that they are not as a rule brush which may be economically manufaccapable of operating at sharp angles and I tured and which is thoroughly eflicient in the have therefore produced and disclosed in the performance of its intended functions. drawings a flexible shaft which is capable 1 v of such operation. The shaft embodies coaxial coil springs 6 and 6", (see Fig. 5), the latter of which extends through the former and is preferably coiled in the opposite direction. In a small tool of the character under consideration, two coaxial springs are found to give very satisfactory results. I find that with such a construction, each spring may be made relatively light, but their aggregate strength will be thoroughly effectual in carrying the load imposed upon the resulting flexible shaft and the shaft will function with far greater efficiency than is possi is if a single spring of much heavier weight is employed for this purpose. Furthermore, a shaft embodying con-centric springs is much more flexible than a shaft embodying a single spring andheavier weight.

The arm .2 of the handle frame is shown as solid but is provided near its free end and on its inner face with a bayonet slot. "4' hav ing an enlarged mouth. The other arm 8 is hollow or tubular and the flexible shaft is adapted to be led through this tubular arm to be connected to a brush positioned between the ends of the arms 2 and In the construction of Figure 1, the flexible shaft projects a short distance beyond the end of the arm 3 and fits into the hub 12 of a brush. This hub is sufiiciently long to engage with the bayonet slot 7 which forms a bearing therefor. In the construction of Figure 7, however, the shaft extendsfroin the end of the arm 3 across the space between said arms and finds a bearing in the bayonet slot.

In practice, the novel form of shaft construction shown in Figure 5 may extend the entire distance from the brush through the arm 3 and conduit 5 to the prime mover. This arrangement is shown in Figure 7. I prefer, however, in practice, to extend this specially formed shaft with its coaxial convolutions, so that it will extend only from the brush to substantially the end of the con duit 5, as shown in Figure 1, and the shaft which extends through the conduit is made somewhat heavier and is joined to the shaft 6, formed in accordance with Figure. 5, by a sleeve 9.

The brush shown in Figures 1 to 1 is provided, as stated, with a hub 12. This hub is formed at one end with a substantially cylindrical part having therein a squared or polygonal opening into which one end of a flexible shaft 6 is adapted to seat. Said end of the shaft is preferably provided with a suitable tip 8 towhich both of the coils 6 and 6 are firmly secured, soas to provide for proper driven connection between the hub and the shaft. Beyond the substantially cylindrical portion of the hub, said hubis formed into asubstantially hour glass shaped cross section, as shown best in Figure 42,

while the free end ofthe hub is slotted axially, as shownat 19. The bristles 26 of the brush are wrapped into and firmly gripped by the convolutions of two lengths of wire 21, which are twisted together to grip the bristles after the manner usual in the manu facture of so-called wire back brushes.

After the bristles have been secured to the wire, the wire is bent about the hub 12 after the manner shown in Figure 2, so as to extend along the channeled sides of the hub and rest in said channel in such manner as to secure the parts against rotation. The slot 19 allows the bristle portion of the brush to be moved into a position to expose the free end of the hub in order that said free end may be entered into the bayonet slot '7 which forms a bearing therefor. As stated, the mouth of the bayonet slot is enlarged to permit of the entry of the hub end thereinto, but said hub is provided with circumferential depressions 22 which permit of rotation of the hub in the upper smaller end of the slot and at the same time preclude withdrawal f the hub from the slot.

With this arrangement, it will be apparent that when the end of the hub is disengaged from the slot, a brush and hub assembly may be readily positioned on or removed from the tip 8 of the flexible shaft and when the brush is on the shaft, the end of the hub may be hooked into the slot after the same manner as securing the, tongue of a safety pin in position.

This ability to readily remove or replace a brush permits each member of a family to have his own individual brush and to readily associate it with the apparatus when he or she desires to brush his teeth.

I have found that when a twisted wire brush is associated with the hub in the manner desired that the natural resiliency of the wires 20 will cause them to tightly grip the hub so that there will be no tendency of the wires to become disengaged from the hub. It will of course be also understood that in the making of the brush, the bristles are trimmed after the wires 20 have been put over the hub, so as to produce a brush of the desired contour.

The device is provided with a suitable guard 15 int-he form of a cowl having seg mental ends 16 in which depressions 17 are formed. The ends of the cowl are more or less resilient and permit the depressions to be sprung over trunnions 18 formed on the frame as clearly shownin Figures 1 and 3. By mounting the guard as described, it will be apparent that said guard may be swung from the dotted to the full line position of Figure 6 and vice versa in order to expose either side of the brushfor use.

The form of brush which I have shown in Figures 1 to 1 is extremely simple and economical to manufacture, although other forms of brush may be used. For example, Figure 7 to 9, a thoroughly practical, though more expensive brush is illustrated. Here the shaft is formed so as to extend through the brush to find the bearing in the slot 7 In this form of the invention, that portion of the shaft which extends through the brush is provided with flattened sides and is adapted to extend through a tubular bushing 29, the opposite sides of which are flattened as shown at 10, so that the bushing is locked against rotation with respect to the shaft. The bushing 29 is permanently fixed on the shaft and forms a support for the brush 11. This brush is provided with a hub in the form of a sleeve 12, the opposite sides of which are flattened to fit over the bushing 29 and around the outer surfaces of the sleeve the bristles are mounted. These bristles may be secured to the sleeve in any suitable manner. I find it, in practice, convenient to construct the brush in the following manner. Two lengths of wire are twisted together in such manner as to twist into the convolutions suitable bris tles. This operation produces a relatively long brush of relatively light weight. This twisted wire, designated 13 in the drawings, with the bristles 14 secured in the convolutions thereof, is then wrapped tightly about the sleeve 12 with the convolutions of the wrapping relatively close to one another, so as to give a relatively thick brush, i. e., a brush with the bristles fairly close to one another.

At the conclusion of the wrapping operation, the two ends of the twisted wire assembly 13 are permanently secured to the sleeve 12 and the bristles are thereupon trimmed to form the outer periphery of the brush into a substantially cylindrical contour.

The brush of the character described can be readily positioned on or removed from the bushing 29 by simply disengaging the end of the bushing from the bayonet slot and swinging out the bushing into the dotted line position of Figure 7. After a brush has been positioned upon the bushing, the bushing is swung back into the position in full lines in Figure 7, wherein it is engaged with the bayonet slot which maintains the parts in operative relation. The natural resiliency of the shaft; will keep the end of the bushing in the slot It will be apparent from the foregoing de tailed description that the structure is unusually simple, yet it clearly fulfills all requirements for the efficient brushing of teeth. The flexible shaft operates at all times in the same direction and the brush, while mounted directly on the shaft, i. e., without intermediate gearing or universal V joint connections, is nevertheless positioned made of metal, celluloid or any other suitable material and the same is true of the guard.

The accompanying drawings show the invention in its preferred practical form, and the invention is to be understood as fully commensurate with the appended claims.

I have particularly referred to the brush as driven by coaxial coil springs. But I wish it understood that the flexible shaft may be of any suitable construction embodying one or more coil springs or otherwise formed so long as it will drive the brush at right angles to the axis of the handle.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. In a device of the character described, a yoke-like frame, a flexible shaft extending through one arm of the frame and beyond the end of said arm, a hub, one end of which is carried directly by the shaft and the other end of which is journaled in the frame, and a brush mounted on said hub between the arms.

2. In a device of the character described, a yoke-like frame, one arm-of which is hollow and the other arm of which is provided at-its free end with a bayonet slot, 2. flexible shaft extending through the hollow arm of the frame and beyond the end of said arm, a hub carried at one of its ends by the flexible shaft and detachably engaging with the bayonet slot in the other arm, and a brush em bracing the hub between said arms.

3. In a device of the character described, a yoke-like frame, one arm of which is hollow and the other arm of which is provided at its free end with a bayonet slot, a hub extending between the arms of the yoke with one end of the hub journaled in the slot, 2. flexible shaft extending through the hollow arm of the frame and beyond the end of said arm and detachably engaging with the hub to drive the latter, a brush mounted on said hub, a cowl like guard pivotally supported on the yoke and adapted to be swung from one side to the other of the yoke to selectively render opposite sides of the brush operative.

4. In a device of the character described, a yoke frame, one arm of which is hollow, a brush positioned cross axially of the axis of said frame and between the arms of the frame, a flexible shaft ext-ending through said hollow arm and into andat least partially through the brush, whereby the flexible shaft forms a support for one end of the brush, and means for journalling the other end of the brush for rotation on the other arm of the frame.

5. In a device of the character described, a yoke frame, one arm of which is hollow, a brush positioned between the arms of the frame and extending cross axially of the frame, a flexible shaft extending through the hollow arm of the frame and beyondthe-end of said arm into and through the brush, and a trunnion secured to theflexible shaft c0- axially of the brush and associated with a bearing in the other arm of the frame, whereby the trunnion and flexible shaft support the brush for rotation.

6. In a device of the character described, a yoke frame, one arm of which is hollow, a brush extending cross axially between the arms of the frame and mounted for rotation with respect to the arms of the frame, and a flexible shaft extending through the 1101- low arm of the frame and beyond the end of said arm into and through the brush to impart rotation to the latter.

7. In a device of the character described, a yoke frame, one-arm of which is hollow, a brush extending cross axially between the arms of the frame and mounted for rotation on the arms of the frame, and a flexible shaft extending through the hollow arm of the frame and beyond the end of said arm into and through the brush to impart rotation to the latter, said flexible shaft comprising a plurality of coaxial coil springs with convolutions of adjacent springs coiled in opposite directions to render the shaft flexible and capable of driving the cross axially disposed brush to which it is directly connected.

In testimony whereof I have signed the foregoing specification.

EDWVIN S. BROTHERS.

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